Glue applicator for corrugated paper machine

ABSTRACT

A glue applicator for corrugated paper machines of the type in which a dip roll dips into a glue vat at one place around its periphery and engages the periphery of a glue applicator roll which rolls on the surface of a moving corrugated paper web, characterized in that the glue applicator roll is provided with a circular or spiral groove so as to apply separated spots of glue to the respective corrugations of the web.

United States Patent Beck et al. 14 1 Sept. 5, 1972 [54] GLUE APPLICATOR FOR 2,589,966 3/1952 Rullo ..118/24] UX CORRUGATED PAPER MACHINE 726,363 4/1903 Sisson ..l 18/242 [72] Inventors: Hansludwig Beck, Bochum; Helmut figfg: 3x3 g l et 12 Brandenburg Wuppertal-Elberfeld l b th fG 2,293,125 8/1942 Fanselow ..118/261 X emmy 3,204,602 9/1965 Farara ..118/262 x [73] Assignee: Gebr. Eickhoff Maschinenfabrik und 3,303,814 2/ 1967 Nitchie ..1 18/262 X Eisengiesserei m b l-[ 'B gh 3,520,276 7/1970 Martin ..118/262 X Germany Pr E J h P M I h imary xaminer o nc ntos [22] Filed June 1970 Attorney-Brown, Murray, Flick & Peckham 21 Appl. No; 44,184

[ 7] ABSTRACT 521 US. Cl. ..118/221, 118/242, 118/262 A glue applicator for Corrugated Paper machines of 51 1111.01. ..Bose l/08, B056 1/16 the type which a dip dips into a glue at one [58] Field 61 Search ..118/212, 216, 261, 211, 242, Place amuhd i P engages the Periphery 118/262 241 203 221 of a glue applicator roll wh1ch rolls on the surface of a moving corrugated paper web, characterized in that [56] References Cited the glue applicator roll is provided with a circular or spiral groove so as to apply separated spots of glue to UNITED STATES PATENTS the respective corrugations of the web.

2,384,676 9/1945 Hill ..118/21 1 UX 6 Claims, 5 Drawing Figures msmtnsv 1m- 3.689.736

FIG. 4. 7 F/a5.

IN VEIV T0178.

HANSCLUDW/G BECK 8 HELMUT BRA/VDENBURG 6J2, Ma W- A f farneys Osbi/ laf'ing GLUE APPLICATOR FOR CORRUGATED PAPER MACHINE BACKGROUND OF THE INVENTION In the usual corrugated paper machine, a glue applicator is provided comprising a glue applicator roll which dips into a glue vat or which engages a second, dip roll which dips into the glue vat and transfers the glue to the applicator roll. A doctor roll rotates with the applicator or dip roll and is in engagement therewith 1 such that only that film of glue which is necessary for sealing corrugations with a covering web remains on the periphery of the roll in the exact thickness required.

In the usual corrugated paper machine, this glue film extends over practically the entire width of the paper web or otherwise over the entire ridges of the corrugations. It acts to sea] the corrugations and the covering web together when they pass, for example, between a lower toothed roll and a press roll which .are both heated. Only enough glue which is necessary for perfect gluing should be applied to the ridges of the corrugations. Too much glue reduces the quality of the corrugated paper which is produced. Moreover, the production of corrugated paper by the use of excessive glue becomes expensive due to the high cost of the glue and the increased heat requirement for drying the adhesive joint. Frequently, an excessive application of glue results in warping of the corrugated paper due to the increased moisture. Thus, crooked sheets which can only be processed with difficulty are formed. For these reasons, it has been common to provide the surfaces of the glue applicator rolls with screens which consist of small, uniformly arranged cups which, for example, have the shape of a pyramid and are separated from each other by raised screen crosspieces. With the use of these screens, a point application of the glue on the ridges of the corrugations can be obtained so as to reduce the amount of glue applied to the product during the production of corrugated paper.

SUMMARY OF THE INVENTION In accordance with the present invention, a new and improved glue applicator for corrugated paper machines is provided which applies only separated spots of glue to the respective corrugations of the web and, hence, eliminates the possibility of an excessive glue application. The invention is characterized by the fact that the periphery of the applicator roll isprovided with circular or spiral grooves in its face which are preferably separated by a distance equal to the width of each groove. With this arrangement, only the circular or spiral crosspieces which remain between the grooves transfer the film of glue which is taken from a dip roll surface onto the corrugation ridges of the paper and produce point applications of glue. The spacing between the individual points of glue application is, of course, determined by the width of the grooves.

Prior art applicator rolls which are provided with screens and which release their glue from the screens and thus from the pyramid-shaped depressions which are filled with glue are limited in the rotational speed at which the applicator roll can rotate. Furthermore, the quantities of glue which are deposited with such prior art applicator rolls differ greatly as the speed of rotation of the applicator roll is increased. In the present invention, on the other hand, the amount of glue applied 0 paper machine or an increase in operating speed of the stantly remove the glue which enters the grooves.

. In one embodiment of the invention, the glue applicator roll and the doctor blade which is coordinated with it are oscillated in a direction along the axis of the applicator roll, the amplitude of the oscillations corresponding to the groove width and the frequency of the oscillations being dependent upon the rotational speed of the glue applicator roll. In this manner, the glue points of succeeding corrugation ridges are shifted by a groove width, and better durability of glue between the individual paper webs is obtained.

The peripheral face of the glue applicator roll can be provided with a single or multiple thread, in which case the grooves will extend spirally around the applicator roll. In this case, a glue application which is shifted from ridge to ridge on the corrugations can be obtained without any oscillatory motion. Preferably, the glue applicator roll should then be provided with two countercurrent thread sections which both have a pitch which presses the corrugated paper web outwardly toward the ends of the rolls. In this manner, any sideward movement of the paper web due to its passage over spiral or screw-type ridges is prevented. The channels which are formed between the thread courses inthis case can be cleaned with blow nozzles which are directed onto the peripheral face of the glue applicator roll. Preferably, the threads or rings between the grooves of the glue applicator roll have a trapezoidal profile. However, the grooves of the glue applicator roll or the channels which are present between the thread courses can also be profiled so as to be semicircular.

The above and other objects and features of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings which form a part of this specification, and in which:

FIG. 1 is a schematic side view of the glue applicator of the invention;

FIG. 2 is a plan view of one embodiment of the glue applicator roll'of the invention showing its relationship to a comb-like doctor blade;

FIG. 3 illustrates a further embodiment of the invention wherein the glue applicator roll is provided with spiral grooves, forming threads; and

FIGS. 4 and 5 are cross-sectional views illustrating different profiles of the grooves in the applicator rolls of FIGS. 2 and 3.

With reference now to the drawings, and particularly to FIG. 1, a dip roll 1 rotates in the direction indicated by the arrow and dips into a glue vat 2 at its lower peripheral section. The dip roll 1 has a smooth, cylindrical peripheral face which is engaged by a doctor roll 3 which rotates in the direction of the arrow shown (i.e., in the same direction as dip roll 1). The doctor roll 3 smooths out the glue on the peripheral surface of the dip roll 1 and leaves a suitably thick glue film on roll 1 since an approximately 0.1 to 0.3 millimeter wide slot exists between the peripheries of rolls 1 and 3. A doctor blade 4 extends over the length of doctor roll 3 and scrapes the excess glue off, insofar as it might still be on the periphery of the doctor roll, and directs it back into the vat 2.

An applicator roll 5 is in peripheral contact with the dip roll 1 and rotates in the opposite direction as indicated by the arrow. The periphery of the applicator roll 5 also engages the ridges of corrugations 6 to which is applied a paper sheet or web, not shown. As will be understood, the corrugations 6 move from right to left as viewed in FIG. 1 as the applicator roll 5 rotates, whereby there is very little sliding movement between the roll 5 and the corrugations 6.

One embodiment of the applicator roll 5 is shown in FIG. 2 and has a peripheral face provided with circular grooves 7 which have either a trapezoidal section, as in FIGS. 2 and 4, or a curved profile such as that shown in FIG. 5. Only the smooth projecting circular faces of the rings formed on the periphery of roll 5 engage the corrugations 6 and thus. transfer the glue film onto the ridges to produce point glue applications with the individual glue points separated from each other by an ainount equal to the width of the grooves 7. In this manner, the glue consumption is greatly reduced, and the heat energy for drying the adhesive bond after the application of the lower paper layer, not shown, is reduced. In order to prevent the grooves 7 from being clogged due to glue residues, a comb-like doctor blade 8 meshes in grooves 7 or roll 5 with projections profiled so as to conform to the shape of the grooves. The doctor blade 8 keeps the grooves 7 free from glue residue as explained above.

A more durable adhesive bond can be obtained if the glue applicator roll 5, together with the doctor blade 8, are permitted to execute an oscillatory motion along the axis of the roll 5 as indicated by the double arrow 9 in FIG. 2. This oscillatory motion -is produced by a suitable oscillating means, schematically illustrated at l l. The amplitude or extent of the oscillatory motion is at least equal to the width of the grooves 7. As will be understood, the frequency of the oscillations back and forth of the roll 5 will be dependent upon the rotational speed of the roll and the corrugations 6.

In FIG. 3, another embodiment of the invention is shown which applies glue points displaced from ridge to ridge without requiring an oscillatory motion of the applicator roll. This is accomplished by providing in the periphery of the glue applicator roll a single or multiple thread 10 which has a profile corresponding to that of FIGS. 2, 4 or 5. In order to avoid the possibility of having the corrugations 6 pushed to the left or right of their forward direction of movement, two countercurrent thread sections 10 are provided. Their pitches run so that they press the corrugated web outwardly on both sides whereby the frictional forces which they cause are balanced. The periphery of the applicator roll is provided w'th circular or spiral grogyes in its face which are pre erably separated by a stance equal to the width of each groove. The grooves 7 of the applicator roll 5' shown in FIG. 3 can be kept clean by blow nozzles which are directed onto the periphery of the roll.

Although the invention has been shown in connection with certain specific embodiments, it will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.

We claim as our invention:

1. A glue applicator for corrugated paper machines comprising a glue vat, a dip roll which dips into said glue vat, a glue applicator roll in peripheral contact with said dip roll and adapted to engage the ridges of corrugations which are to-be glued to a paper web, grooves formed in the periphery of said applicator roll and extending around its circumference whereby only the peripheral surfaces of said applicator roll between said grooves will engage the ridges of said corrugations to apply to said ridges spaced patches of glue, and the grooves having a trapezoidal profile in which the sides of the profile extending radially of the axis of said applicator roll diverge from one side of the profile to the other.

2. The glue applicator of claim 1 including a comb like doctor blade having tooth-like projections which project into the grooves of said applicator roll.

3. The glue applicator of claim 1 including means for imparting an axial oscillatory motion to said applicator roll, the amplitude of the oscillations and the frequency of the oscillations being such that the glue patches on succeeding ridges of the corrugations are displaced with respect to each other by the width of a groove.

4. The glue applicator of claim 1 wherein said grooves extend spirally around the circumference of said applicator roll to form threads which engage the ridges of said corrugations.

5. The glue applicator of claim 4 characterized in that said spiral grooves form two countercurrent thread sections having reversed pitches.

6. A glue applicator for corrugated paper machines comprising a glue vat, a dip roll which dips into said glue vat, a glue applicator roll in peripheral contact with said dip roll and adapted to engage the ridges of corrugations which are to be glued to a paper web, grooves formed in the periphery of said applicator roll and extending around its circumference whereby only the peripheral surfaces of said applicator roll between said grooves will engage the ridges of said corrugations to apply to said ridges spaced patches of glue, the grooves extending spirally around the circumference of said applicator roll to form two countercurrent thread sections having reversed pitches which engage the ridges of said corrugations and the peripheral surfaces of the roll between said grooves having widths essentially the same as those of the grooves themselves. 

1. A glue applicator for corrugated paper machines comprising a glue vat, a dip roll which dips into said glue vat, a glue applicator roll in peripheral contact with said dip roll and adapted to engage the ridges of corrugations which are to be glued to a paper web, grooves formed in the periphery of said applicator roll and extending around its circumference whereby only the peripheral surfaces of said applicator roll between said grooves will engage the ridges of said corrugations to apply to said ridges spaced patches of glue, and the grooves having a trapezoidal profile in which the sides of the profile extending radially of the axis of said applicator roll diverge from one side of the profile to the other.
 2. The glue applicator of claim 1 including a comb-like doctor blade having tooth-like projections which project into the grooves of said applicator roll.
 3. The glue applicator of claim 1 including means for imparting an axial oscillatory motion to said applicator roll, the amplitude of the oscillations and the frequency of the oscillations being such that the glue patches on succeeding ridges of the corrugations are displaced with respect to each other by the width of a groove.
 4. The glue applicator of claim 1 wherein said grooves extend spirally around the circumference of said applicator roll to form threads which engage the ridges of said corrugations.
 5. The glue applicator of claim 4 characterized in that said spiral grooves form two countercurrent thread sections having reversed pitches.
 6. A glue applicator for corrugated paper machines comprising a glue vat, a dip roll which dips into said glue vat, a glue applicator roll in peripheral contact with said dip roll and adapted to engage the ridges of corrugations which are to be glued to a paper web, grooves formed in the periphery of said applicator roll and extending around its circumference whereby only the peripheral surfaces of said applicator roll between said grooves will engage the ridges of said corrugations to apply to said ridges spaced patches of glue, the grooves extending spirally around the circumference of said applicator roll to form two countercurrent thread sections having reversed pitches which engage the ridges of said corrugations and the peripheral surfaces of the roll between said grooves having widths essentially the same as those of the grooves themselves. 